Folding tracing-slate



(No Model.)

W. D. HEYER.

FOLDING TRAGING SLATE. No. 365,182. Patented June 21, 1887.

a2 '7 F a j l n!!! a V A 1" N WITNESSES I INVENTOR I g i BY MIAMI/g ATTORNEYS.

NITED STATES PATENT QFFICEQ \VILLIAM D. HEYER, OF ELIZABETH, NE\V JERSEY. I

FOLDING TRAClNG-SLATE.

SPECIFICATION forming part of Letters Patent No. 365,182, dated June 21, 1887.

Serial No. 215,268. (No model.)

To all whom it may concern:

Be it known that I, \VILLIAM D. HEYnn, of Elizabeth, in the county of Union and State of New J erscy,have invented a new and Improved Folding Tracing-Slate, of which the following is a full, clear, and exact description.

My invention relates to an improvement in tracing-slates, in which a translucent slate is combined with an opaque ground, whereby a slate-pencil may be used upon the roughened surface of the said translucent slate, the white lines produced by said slate-pencil being rendered clearly visible by reason of the dark background.

The object of my invention is to so inclose the translucent slate between ordinary hinged opaque slates as that the said translucent slate will be protected from injury, and the writing or drawing upon both forms be preserved from danger of erasure, and also to afford ample independent surface for both tracing and copying.

The invention consists in the construction and combination of the several parts, as will be hereinafter fully set forth, and pointed out in the claims.

Reference is to be had to the accompanying drawings, forming a part of this specification, in which similar letters of reference indicate corresponding parts in all the figures.

Figure 1 is a front elevation of my improved tracing-slate in position for use, the attached translucent slate being partially broken away. Fig. 2 is a central horizontal section through Fig. 1, showing the attached translucent slate partially elevated; and Fig. 3 is a central longitudinal section through my slate when folded.

AA represent two opaque slates,which may be ordinary school-slates, or slates made up of any opaque material suitable for the purpose, provided with ordinary hinges, 0, whereby the one is adapted to fold over upon the other. The upper and lower transverse portions, a a, of the frame of slate A are made slightly narrower than the corresponding portions of the frame surrounding the slate A, and the said slate A is also provided upon the inner side of the outer longitudinal strip of the frame with one or more inwardly-curved recesses, b, for a purpose hereinafter stated.

A rectangular piece of ground glass, B, or

other equivalent translucent material, is provided to fit loosely within and cover the sight bounded by the frame of the slate A, the said ground glass B being attached preferably to the inner longitudinal strip of said frame by means ofa flexible hinge, d.

The object of the curved recesses b, above referred to, is to afford a hold upon the translucent slate B, to raise the same, in order to produce a copy directly upon the opaque surface ofthesiate A, or to introduce an opaque card under said translucent slate, having a copy formed thereon in white lines, and the purpose of the reduced top and bottom piece of the frame in slate A is to afford a bearing upon the upper and lower surfaces of the translucent slate B for the top and bottom sections of the frame of the slate A when the two slates are closed, as shown in Fig. 3,whereby the said translucent slate is held securely in position and rendered free from displacement and consequent injury.

The operation is as follows: The folding slate being opened, the translucent slate B is raised, and a card containing a design in white upon a black ground is laid upon the opaque slate A, or the design produced directly upon said slate. The translucent slate B is new lowered in position and the design traced upon the rough surface of the glass slate with a slatepeneil. After some knowledge of the subject has been acquired, by the tracing-process the design is copied in free hand upon the opposite opaque slate A.

I am aware that folding slates consisting of two or more opaque slates hinged together are old, and also that a tracing-slate for use with a slate-pencil has been produced wherein a translucent plate is made to cover a portion of an opaque slate, as a patent for such a combination was granted myself bearing date May 6, 1884.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. An improved article of manufacture, con sisting of a translucent slate held between hinged opaque slates, the said translucent slate adapted to cover the inner surface of one of said hinged slates, substantially as shown and described,and for the purpose herein set forth.

2. The combination, with an opaque slate size, hinged thereto, having an ordinary frame, 10 having another slate hinged thereto, of a transof a translucent slate held between said hinged lucent slate held between said opaque slates slates, substantially as shown and described, to cover the inner surface of one only, substanand for thepurpose herein set forth.

5 tially as shown and described, and for the purpose herein set forth. WILLIAM HEYER' 3. The combination, with the opaque slate \Vitnesses: A, provided with a frame having a narrow top ALFRED D. OROWELL,

and bottom strip, and a slate, A, of similar 0. G. ORowELL. 

